
Next, we present a \(C^0\) -continuous interior penalty HDG (CIP-HDG) discretization of the
equation (REF ). We didn't find in the literature on publications on
CIP-HDG formulations for the generalized biharmonic equation, but it can be
easily adapted from a known CIP-DG scheme [1]}.
We mention that the implementation of a version of the CIP-HDG scheme for the
biharmonic equation was already used in unit 2.9 of the i-tutorials
of the NGSolve software [2]}.
